When a well is drilled, production casing is set so that the well can be properly cemented and the production zone(s) do not have fluid communication, with other geological strata. The production zone is logged and then the production casing is perforated so that oil and/or gas can be drained from the production zone into the production casing of the well. Traditionally, hydrocarbon wells were drilled vertically down to and through one or more hydrocarbon production zone(s). As shown in FIG. 1, a vertical wellbore 10 having a production casing 12 passes through a hydrocarbon production zone 14. A plurality of perforations (not shown) formed in the production casing 12 using methods well known in the art permit hydrocarbons 16 to flow into the production casing 12. The casing perforations also permit the production zone 14 to be treated to stimulate production by creating a plurality of fractures 18 in the production zone 12 using, for example, hydraulic fracturing techniques that are well known in the art. A production tubing 20 is used to deliver the hydrocarbons 16 to the surface. A packer 22 seals the annulus between the production tubing 20 and the production casing 12.
Vertical wellbores have now been substantially abandoned in favor of more productive lateral wellbores that provide more exposure to the production zone. Although the first recorded true lateral well was drilled near Texon, Tex. in 1929, new technology developed over the last decade has permitted lateral drilling techniques to rapidly evolve. Hydrocarbon wells are now drilled vertically to a point above the production zone and then curved so that the wellbore enters the production zone at an angle and continues laterally within the production zone for more in-zone exposure to the hydrocarbon bearing formation. Some production zones are up to 300 feet (91.5 meters) thick, or more, and with lateral drilling techniques casing can be run up to 8,000 ft. (2.44 kilometers) into the production zone, thus providing significantly more area for hydrocarbons to drain into the production casing.
FIG. 2 is a schematic cross-sectional diagram of an exemplary prior art hydrocarbon well 30 with a lateral wellbore. Well know features such as the conductor and surface casing are not shown. A vertical section 32 of the hydrocarbon well 30 is drilled down into proximity of a production zone 14, cased and cemented in a manner well known in the art. In many areas, the vertical section of the well may be 10,000 feet (3.05 kilometers) in length. In some areas the vertical section may exceed 10,000 feet (3.05 kilometers) in length. A curved section 34 of the hydrocarbon well 30 is then drilled into the production zone 14. Once it is established that the curved section 34 is in the production zone 14, a lateral wellbore 36 is drilled in a desired direction in as straight a path as possible within the production zone 14. Recent innovations in work strings for completing lateral wellbores described in applicant's co-pending U.S. patent application Ser. No. 14/735,846 filed Jun. 10, 2015, the specification of which is incorporated herein by reference, permit lateral wellbores of at least 12,000 feet (3.66 kilometers) to be successfully completed. After the lateral wellbore 36 is drilled, a production casing 38 is run into the lateral wellbore 36. The production casing 38 is generally “cemented in” before it is perforated for production. In any event, sections of the production casing 38 are perforated and stimulated using methods known in the art until an entire length of the production casing 38 has been perforated and the surrounding production zone 14 has been stimulated. A production tubing 42 is then run into the well and a packer 44 is set to seal the annulus. In a very long lateral bore, stimulation of the production 14 surrounding the lateral well bore 36 is a major undertaking and now costs more than drilling, casing and cementing the bore. Once stimulation and flow-back of stimulation fluids are completed, production of hydrocarbons from the wellbore 30 begins. In a shale basin such as found in the Bakken, play, production is generally commercially viable for about 2 years, and may be extended by reworking the well using methods known in the art.
While the lateral wellbore method has been commercially successful, the potential for innovative production strategies has yet to be realized.
There therefore exists a need for a novel method of completing and producing long lateral wellbores.